#include "mystdio.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

static MyFile *BuyFile(int fd, int flag)
{
    MyFile *f = (MyFile*)malloc(sizeof(MyFile));
    if(f == NULL) return NULL;
    f->bufferlen = 0;
    f->fileno = fd;
    f->flag = flag;
    f->flush_method = LINE_FLUSH;
    memset(f->outbuffer, 0, sizeof(f->outbuffer));
    return f;
}

MyFile *MyFopen(const char *path, const char *mode)
{
    int fd = -1;
    int flag = 0;
    if(strcmp(mode, "w") == 0)
    {
        flag = O_CREAT | O_WRONLY | O_TRUNC;
        fd = open(path, flag, 0666);
    }
    else if(strcmp(mode, "a") == 0)
    {
        flag = O_CREAT | O_WRONLY | O_APPEND;
        fd = open(path, flag, 0666);
    }
    else if(strcmp(mode, "r") == 0)
    {
        flag = O_RDWR;
        fd = open(path, flag);
    }
    else
    {
        // TODO
    }
    if(fd < 0) return NULL;
    return BuyFile(fd, flag);
}
void MyFclose(MyFile *file)
{
    if(file->fileno < 0) return;
    MyFFlush(file);
    close(file->fileno);
    free(file);
}
int MyFwrite(MyFile *file, void *str, int len)
{
    // 1. 拷贝
    memcpy(file->outbuffer+file->bufferlen, str, len);
    file->bufferlen += len;
    // 2. 尝试判断是否满足刷新条件！
    if((file->flush_method & LINE_FLUSH) && file->outbuffer[file->bufferlen-1] == '\n')
    {
        MyFFlush(file);
    }
    return 0;
}
void MyFFlush(MyFile *file)
{
    if(file->bufferlen <= 0) return;
    // 把数据从用户拷贝到内核文件缓冲区中
    int n = write(file->fileno, file->outbuffer, file->bufferlen);
    (void)n;
    fsync(file->fileno);
    file->bufferlen = 0;
}







